Generally, two shuttle car operators have no trouble keeping track of each other on their way from the continuous miner to the dumping point and back. However, a recent fatality occurred when a shuttle car ran into the other shuttle car at the dumping point. Today's larger "super sections" may run four to six shuttle cars behind two continuous miners and have a single dumping point. This has proven to cause traffic jams at the dumping point that can result in confusion, collisions, and injuries. A simple remedy is to install traffic lights at the dump point that can be seen from any approach. This does not mean that a timed "red light" like at a highway intersection be used, but a series of switches that are convenient to the shuttle car operators. A wobble type switch, much like the "slap switches" used in the track haulage areas of many mines, that alternately turns a green or red light on would work perfectly. If the operator is approaching the dumping point and the light is green, he can proceed. As he passes the slap switch, he gives it a whack, changing the green light to red. This will warn any other operator that the dump point is occupied. After dumping the load, he again slaps the switch on the way out, turning the red light back to green, telling the other operators that the dump point is free. Redundant bulbs in the signal are recommended to ensure that a burned out bulb does not cause a breakdown in the communication system.
If standard and off standard shuttle cars are using the same dump point approach, it may be necessary to place a slap switch on both sides of the entry since a switch mounted in the center of the entry may not be accessible to both.
Whether the power for the system is derived from a power center or the trolley wire, make sure that adequately sized circuit breakers or fuses are used.
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